The geographical environment of Changchun

Changchun is located at 43 05' ~ 4515' north latitude; East longitude12418' ~12705' is located in the north temperate zone in the middle latitude of the northern hemisphere, and the main city is located in the Yitong River platform in the hinterland of Songliao Plain. It is adjacent to Songyuan City in the northwest, Siping City in the southwest, Jilin City in the southeast and Heilongjiang Province in the northeast. The perimeter of the city boundary is about 3298.97 kilometers.

Changchun is located in Songliao Plain, the hinterland of China Northeast Plain on the east coast of Eurasia. It is the physical geographical center of northeast China, the geometric center of northeast Asia and the core of the trans-economic corridor of northeast Asia. The total area is 20565 square kilometers, of which the urban area is 7557 square kilometers. In 20 14, the built-up area was 452 square kilometers, ranking 12 in China.

Changchun-Siping deep fault is a main structural line separating mountains and plains, with uplift area in the east and subsidence area in the west, and Changchun area is located between uplift area and subsidence area. The transition of geological structure determines the diversity of landform types in Changchun, forming the landform characteristics of high in the east and low in the west.

The landscape of Songliao Plain consists of mountains, terraces and plains, forming a landscape pattern of "one mountain, four hills and five rivers". The mountainous area of Changchun City is small, accounting for about 9% of the total land area of Changchun City. Among them, low mountains account for 2.56% and hills account for 6.44%. Jilin mainly includes Daheishan and Hadaling. The ground of Changchun Station is very large, accounting for about 4 1% of the total land area. Among them, flat terraces account for 35.23% and high terraces account for 5.77%. There are mainly Yushu Terrace, Changchun Terrace, Double Balcony and Youlongquan Terrace. Changchun platform has the largest area, accounting for about 50% of the total land area. Among them, valley plain accounts for 39.4%, low terrace accounts for 7.5%, and lake plain accounts for 3. 1%. There are mainly Shuangyang Basin, Songhua River Valley Plain, Lalin River Valley Plain, Yinma River Valley Plain and Nongan Lake Plain.

Changchun City is located in Yitong River terrace, which is the transition zone from the eastern mountainous area of Songliao Plain to the western plain. The terrain is high in the east and low in the west, and the landform consists of platforms and plains. The platform accounts for 70% and the plain accounts for 30%. Different landform types have different constraints on urban construction. Changchun City is located in the hinterland of China Northeast Plain, with an altitude of 250-350 meters and a flat and open terrain. It belongs to the continental monsoon climate zone in the north temperate zone, and is in the transition zone from humid area to sub-arid area in the national dry and wet climate division. The temperature rises from east to west, and the precipitation decreases from east to west. Spring is dry and windy, summer is wet and rainy, autumn is crisp, winter is cold and long, four seasons are distinct, rain and heat are the same season, and humidity is moderate.

The annual average temperature in Changchun is 4.8℃, the highest temperature is 39.5℃, the lowest temperature is -39.8℃, and the sunshine time is 2688 hours. Southeast winds prevail in summer, and there is moisture supplemented by Bohai Sea. The annual average precipitation is 522 ~ 6 15mm, and the summer precipitation accounts for more than 60% of the annual precipitation. The average temperature in the hottest month (July) is 23℃. Autumn can form sunny and warm weather for several days, with large temperature difference and lower wind speed than spring.